This polished and fluted surface atop Independence
Rock, Wyoming can only have been shaped by wind. It's too
high to be the result of water and was never glaciated.

How
old does graffiti have to be before it stops being
vandalism and becomes a historical relic? The "IOWA62"
at lower left refers to 1862. Independence Rock was so
named because travelers on the Oregon Trail tried to get
here by July 4 to be sure of crossing the mountains
before autumn snows began.

Wind-abraded rocks are often called dreikanters
from a South African word meaning "three corners."
Ventifacts are common in the U.S., once you know what to
look for. This perfect dreikanter was found at River
Falls, Wisconsin. Most ventifacts in the northern U.S.
formed during the Pleistocene when vegetation was sparse
and wind-blown sand and silt was abundant.

The largest deflation basin in Wisconsin is near
Spring Green along the Wisconsin River flood plain.

Many deserts are covered with desert pavement,
created when wind blows fine material away, leaving
coarse material behind. This deposit is upwind from Great
Sand Dunes (below).

A deposit of heavy material left
behind when light material is carried away is called a lag
deposit. Lag deposits can be created by wind,
running water, and wave action.

A "desert" pavement forming in a gravel pit
near Hastings, Minnesota.

These longitudinal dunes in Colorado formed when sand
deopped off the masa to the left and collected in the lee
of rocky

Dunes are often hybrids of several types. In this
aerial view, these dunes in Colrado are partially
longitudinal (lower left to upper right) and partially
transverse.

Beach dunes on the shore of Lake Michigan

The largest dune fields in the U.S. are in, of all
places, Nebraska. The Sand Hills cover much of western
Nebraska. They formed during the Pleistocene from glacial
debris eroded out of the Rockies, and exhibit just about
every type of dune. Here we see transverse dunes several
hundred meters wide and a kilometer or so long.

These dunes in the Nebraska Sand Hills are barchan-like
but much bigger and more closely-spaced than most
barchans. They are several hundred meters in size.

Typical appearance of Nebraska Sand Hills country.
The land is mostly used for grazing and is sparsely
settled.

This dune east of Fallon, Nevada, formed from sand
blown across a wide valley. Wind funnels through the low
pass, but cannot carry the sand with it.

The highest sand dunes in the U.S. are Great Sand
Dunes in Colorado. Wind blows sand from the right but
cannot carry it over the mountains as air funnels through
a low pass. The peaks in the foregrouns and the distance
are over 14,000 feet but the pass is only 9,000.

The highest dunes in Great Sand Dunes National
Monument are over 200 meters high.

The most user-friendly wilderness area around. The
area beyond the stream is perhaps the only designated
wilderness area you can walk to in your bare feet.

The
bare peak is over 14,000 feet and is in the foreground of
the aerial photo above. The low pass to the right is
about 9,000 feet. Wind blows sand across a broad basin
but cannot carry it over the pass. The small stream
catches most of the sand that lands east of the dunes and
returns it to the basin to be blown again.

Every type of dune can also from in snow, but good
barchans are rare. These formed near Bay Settlement,
Wisconsin in January, 1997 as snow blew across a frozen
crust.

A barchan snow drift on bay ice off Communiversity
Park in Green Bay, Wisconsin. The blowing snow shows the
air flow over the dune. Wind chill was about -60 when the
picture was taken. My dog, smarter than his master,
hunkered down in a ball and stayed put.

Wind-blown sand has piled against old beach terraces
on the eastern side of former Lake Bonneville in Utah,
outlining them clearly.

The cap on these bluffs along the Mississippi near
Alma, Wisconsin is loess, blown from the Mississippi
River flood plain during the Pleistocene.